This invention relates to methods and apparatus for injection casting metallic fuel rods for use in fast nuclear reactors, and more particularly, to consumable and re-usable molds for use in making metallic nuclear energy fuel rods.
Metallic fuel rods are currently used in fast reactors. Metallic fuel is preferred over ceramic fuel because the natural behavior of metallic fuel counters upset conditions in the reactor, resulting in more stable, safe generation of nuclear energy. Also, metallic fuel is more easily processed and fabricated than ceramic fuel, resulting in more economic energy production.
Metallic fuel rods have historically been cast in quartz molds which are coated on the inside with high temperature ceramic paint. The quartz molds are long, thin tubes which are open at one end. Metallic fuel rods are made in the quartz molds by first placing solid fuel stock in a crucible and placing the crucible in a sealed chamber with a plurality of molds. The fuel in the crucible is melted and the chamber is evacuated. The open ends of the molds are placed in the liquid and the chamber pressure is increased substantially. The increased pressure forces liquid fuel into the cavities of the molds, and when the fuel in the molds has solidified, the molds are removed from the melt.
To extract the fuel from the quartz molds, the quartz molds must be broken. In this process, the molds are destroyed and discarded. This creates an environmental problem, however, because the molds are contaminated with radioactive fuel. Thus, there is a need for methods and apparatus for molding metallic fuel rods which reduce radioactive wastes and thus create fewer environmental hazards.
The one-time use of quartz molds as just described is also relatively inefficient because a mold must be fabricated for each fuel rod produced. Thus, there is also a need for more efficient methods and apparatus for producing metallic fuel rods.
Accordingly, one object of this invention is to provide new and improved methods and apparatus for producing metallic fuel rods for the production of nuclear energy.
Another object is to provide new and improved methods and apparatus for making metallic fuel rods which reduce radioactive waste.
Still another object is to provide new and improved methods and apparatus for making metallic fuel rods which are more efficient than known methods and apparatus.
A still further object is to provide new and improved methods and apparatus for making metallic fuel rods from molds which are consumable with the rods when the fuel is irradiated.
Yet another object is to provide new and improved methods and apparatus for making metallic fuel rods in molds which are at least partially reusable.